Diabetes mellitus type 2 represents a heterogenous disease characterized by impaired glucose homeostasis. The disorder clusters in families suggesting genetic disposition, however the mechanism underlying is unknown. Many studies show more frequent maternal transmission of diabetes in the families. One of huge range of explanation is exclusively maternal transmission of mitochondria. Mitochondria are power organelles which produce ATP molecules by oxidation-reduction reactions via the respiratory chain. They contain their own genome which codes subunits of the respiratory chain and proteosynthetic apparatus for proteins encoded by this genome. Pathogenic mutations of mitochondrial DNA can affect the activity of the respiratory chain and result in various phenotypes. Mitochondrial diabetes is commonly associated with neuromuscular disorders and often presents with nonautoimmune beta cell failure. Although mitochondrial mutations are associated with diabetes, their low frequency does not explain reported more frequent maternal transmission of diabetes mellitus type 2.